1. Field of the Invention
This invention is in the field of accumulator or pulsation dampener devices, and more particularly pertains to an accumulator or like device of the type in which a distensible bladder member is mounted within a pressure vessel, the bladder member dividing the vessel into two chambers communicated, respectively, with a gas charging port and with an oil port.
2. The Prior Art
Accumulator devices have found widespread application as means for storing energy and for dampening pulsations in liquid moving in a conduit. Such pressure devices conventionally include a rigid vessel of sufficient strength to withstand the high pressure to which the same will be exposed in use. The vessel, which is conventionally cylindrical or parti-spherical in shape, includes at one end a gas charging port and at the other an oil port which, in use, is connected to a source of fluid under pressure. A bladder member is disposed within the pressure vessel, the bladder member dividing the interior of the vessel into two chambers of variable size communicating, respectively, with the gas charging port on the one hand and the oil port on the other.
Gas under pressure is introduced through the gas charging port into one said chamber, whereupon the bladder, which typically carries a valve member, is distended in such manner that the valve member engages a complementally formed valve seat to close the oil port.
When pressures in the liquid conduit line to which the oil port is connected exceed the pressures in the chamber connected with the gas charging port, oil enters through the port, driving the bladder away from the seated position above referred to, and compressing the gas within the chamber, whereby pulsations in the oil line are damped and/or energy is stored in the compressed gaseous medium.
As is well known, the pressures within the gas chamber are often extremely high and, thus, when the oil pressure is reduced, the bladder is forced toward the oil port end of the accumulator device with tremendous force. In the event that there are any voids, ridges or irregularities within the pressure vessel in the areas extending from the vessel to the oil port, the pressure differential may be sufficient to extrude the bladder portions surrounding the valve seat through such crevices and into the oil port, resulting in rupture of the bladder or at least in premature wear and degradation thereof.
In view of the necessity for eliminating irregularities in the areas leading to the oil port, it has heretofore been the practice, in the formation of pressure vessels, to fabricate the same through extensive machining operations. Thus, the pressure vessel often will be comprised of two half sections which have been cast or forged, the open half sections providing ready access to the interior of the sections which will form the oil port, to enable facile machining thereof. The halves, after mounting of the bladder assembly, must then be welded together.
It will be readily recognized that forging separate half sections and thereafter machining and welding, coupled with the extreme care which must be taken in the course of the welding operation to prevent damage to the bladder, greatly increased the over-all cost of the accumulator device, with the result that it is often necessary to forego the use of accumulators in many applications in which they would otherwise be desirable.
While it is known that an enclosure having sufficient structural strength to resist the pressures encountered in the course of accumulator operations can be formed by a spinning operation wherein a tubular member is rotated relatively to a forming tool which is progressively urged against the surface of the tube to deform the same to a desired configuration, it is likewise recognized that the configuration resulting from the spinning operation, particularly at the inside of the curve formed in the course of spinning, exhibits irregularities of the type which would be likely to lead, as hereinabove noted, to bladder failure.
Accordingly, despite the economic desirability of spinning as opposed to forging and machining, prior vessels for accumulators have not heretofore been successfully fabricated on a large scale basis utilizing spinning operations without further machining in the critical area adjacent the oil port.
It is known, as indicated by Patents such as U.S. Pat. Nos. 2,399,444, 3,794,078 and 3,960,178 to provide an oil port having a valve seat which is itself formed of rubber and contacts directly a valve carried by the bladder. However, such devices do not contemplate a rigid and hence more wear resistant valve seat in combination with a surrounding buffer member which may also be deflected by the bladder into sealing relation of the area external of the port, in accordance with the present invention.